Further studies of anomalous phenomena in dielectric-loss measurements-transformer bushings model

Author

Levi, Raka ; Manifase, Stan

Author_Institution

Doble Eng. Co., Watertown, MA, USA

Volume

10

Issue

2

fYear

1995

fDate

4/1/1995 12:00:00 AM

Firstpage

889

Lastpage

895

Abstract

The results of AC dielectric loss measurements on bushings mounted in certain three-phase transformers, if not performed in accordance with the prescribed procedure, can deviate significantly from the correct values. An investigation of the incorrect procedure has shown that the capacitive coupling between adjacent windings and the lower portion of the bushings influenced the results such that dielectric losses were elevated to several times their normal values. Experience has shown that bushing test results on all three phases form a pattern in cases where this phenomena is evident. Results of investigative field measurements showing this phenomena are presented, and an explanation of its origin is given

Keywords

bushings; dielectric loss measurement; dielectric losses; electric breakdown; insulation testing; insulator testing; measurement errors; power transformer insulation; power transformer testing; transformer windings; AC dielectric loss measurements; adjacent windings; anomalous phenomena; capacitive coupling; field measurements; three-phase; transformer bushings; Circuit testing; Dielectric losses; Dielectric measurements; Dielectrics and electrical insulation; Insulation testing; Insulators; Performance evaluation; Pollution measurement; Power transformer insulation; Windings;

fLanguage

English

Journal_Title

Power Delivery, IEEE Transactions on

Publisher

ieee

ISSN

0885-8977

Type

jour

DOI

10.1109/61.400841

Filename

400841